The Massachusetts Democrat, known for her critiques of big banks and corporations, became the first major candidate to declare her intentions with a video posted online on New Year’s Eve.

“America’s middle class is under attack,” she said. “How did we get here? Billionaires and big corporations decided they wanted more of the pie and they enlisted politicians to cut them a fatter slice.”

Warren, 69, is entering what is likely to be a crowded Democratic primary field seeking to take on Donald Trump. Those considering bids include a slew of fellow senators such as Cory Booker, Kamala Harris, Kirsten Gillibrand and Bernie Sanders, Joe Biden, the former vice-president, and former New York City mayor Michael Bloomberg.

In her four and a half minute announcement video, Warren stressed the economic populist message that has brought her to national prominence.

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She mixed old family photos with charts showing the declining middle-class share of income and the gap between black and white household wealth, and discussed her upbringing in Oklahoma and her family’s struggle to make ends meet after her father had a heart attack that left him unable to work.

“Working families today face a lot tougher path than my family did,” she said. “Our government’s supposed to work for all of us, but instead it has become a tool for the wealthy and well-connected.”

Warren did not mention Trump by name in the video, but it showed images of him along with allies Kellyanne Conway and Steve Bannon and Fox News personalities Tucker Carlson and Sean Hannity. The video says: “The whole scam is propped up by an echo chamber of fear and hate designed to distract and divide us – people who will do or say anything to hang on to power.”

Every person in America should be able to work hard, play by the same set of rules, & take care of themselves & the people they love. That’s what I’m fighting for, & that’s why I’m launching an exploratory committee for president. I need you with me: https://t.co/BNl2I1m8OXpic.twitter.com/uXXtp94EvY

Warren, a former law professor, gained prominence for her critique of Wall Street after the 2008 financial crash, and proposed what became the Consumer Financial Protection Bureau. She ran for the Senate in 2012, defeating incumbent Republican Scott Brown.

As a senator, she has proposed legislation to overhaul the way corporations operate, requiring them to obtain government charters to operate and consider their public’s interests rather than just those of their shareholders. She gained fans for standing up to Senate majority leader Mitch McConnell on the Senate floor, turning his admonishment of her – “Nevertheless, she persisted” – into a slogan.

But Warren has suffered significant missteps as well, and become a favorite target for conservative critics who paint her as the the epitome of the east coast, academic liberal elite they often disparage.

She drew criticism for the release of a DNA test intended to prove her Native American heritage, which offended some Native American groups and led to doubts about her political acumen. The Cherokee nation secretary of state, Chuck Hoskin Jr, called her move “inappropriate and wrong” and said: “Senator Warren is undermining tribal interests with her continued claims of tribal heritage.”

She is also a favorite target of Trump, whose taunts calling her “Pocahontas” prompted the DNA test. He has also labeled her “Goofy Elizabeth Warren”.

Commenting on Warren’s 2020 announcement in an interview with Fox News, set to air late on New Year’s Eve, Trump said he would “love to run against her”. “So, we’ll see how she does. I wish her well, I hope she does well.”

Even in her heavily Democratic home state, Warren is a polarizing figure. The editorial board of the Boston Globe, noting that she won re-election with fewer votes than Republican Massachusetts governor Charlie Baker, encouraged her not to run for president.

“Those are warning signs from the voters who know her best,” the paper wrote. “While Warren is an effective and impactful senator with an important voice nationally, she has become a divisive figure. A unifying voice is what the country needs now after the polarizing politics of Donald Trump.”

At a press conference Monday afternoon near her Cambridge home where she was joined by her husband and dog, Warren brushed off concerns she could be too polarizing to be elected.

“When we show – not just tell, but show – what Democrats can get out there and make happen, I think that’s how we win,” she said. “The problem we’ve got right now in Washington is that works great for those who’ve got money to buy influence, and I’m fighting against that, and you bet that’s going to make a lot of people unhappy.”

Forming an exploratory committee will allow Warren to begin raising money for the presidential campaign. In past campaigns, she has had success raising small-dollar donations.

Trump has said he would welcome a run against Warren. “I hope she’s running for president, because I think she’d be very easy,” he said in October. “I hope that she is running. I do not think she’d be difficult at all. She’ll destroy the country. She’ll make our country into Venezuela.”

Among progressive groups, reaction on Monday was positive.

“Senator Elizabeth Warren’s formal entrance into the 2020 race for president today helps launch what we believe will be a vibrant discussion of bold, inclusive populist ideas in the Democratic primary, and we look forward to the wide array of progressive candidates that we expect to join her in it in the year ahead,” said Charles Chamberlain, the Democracy for America executive director.